How can you tell that the naf is an inhibitor

What function does the limb sever in each animal? how are the limb bones of the four animals similar? based on these similarities what can be inferred about the evolution of the four animals.

Which of the following must be true for a fossil organism to be useful as an index fossil? a. the fossil organism must be widespread geographically. b. the fossil organism must be abundant. c. the fossil organism must be limited to a short span of geologic time. d. all of the above.

Body temperature is tightly regulated in mammals for example when external temperatures drop too much the body of a mammal response by in order to it's core temperature.